Liquid crystal display device

ABSTRACT

A liquid crystal display includes a first insulation substrate, a gate line, a data line configured to cross the gate line while being insulated therefrom, a thin film transistor connected to the gate line and the data line, a pixel electrode configured to include a first subpixel electrode connected to the thin film transistor and a second subpixel electrode, a second insulation substrate configured to face the first insulation substrate, a common electrode disposed on the second insulation substrate, and a liquid crystal layer disposed between the first insulation substrate and the second insulation substrate to include a plurality of liquid crystal molecules, where each of the first subpixel electrode and the second subpixel electrode includes a unit pixel electrode including a plurality of minute branches that is extended from a horizontal stem and a vertical stem.

This application claims priority to Korean Patent Application No.10-2015-0025398 filed on Feb. 23, 2015, and all the benefits accruingtherefrom under 35 U.S.C. §119, the content of which in its entirety isherein incorporated by reference.

BACKGROUND

(a) Field

Exemplary embodiments of the invention relate to a liquid crystaldisplay.

(b) Description of the Related Art

A liquid crystal display (“LCD”), which is one of the most common typesof flat panel displays currently in use, includes two sheets of displaypanels with field generating electrodes, such as a pixel electrode, acommon electrode, and the like, and a liquid crystal layer interposedtherebetween. In the liquid crystal layer, voltages are applied to thefield generating electrodes to generate an electric field in the liquidcrystal layer. Then, the alignment of liquid crystal molecules of theliquid crystal layer is determined by the electric field to control thepolarization of incident light, thereby displaying images.

Among the LCDs, a vertically aligned mode LCD, in which liquid crystalmolecules are aligned such that long axes of the liquid crystalmolecules are perpendicular to a display panel in a state in which noelectrical field is applied, has been developed.

In the vertical alignment (“VA”) mode LCD, a wide viewing angle isconsidered an important issue, and can be realized by cutouts such asminute slits in the field generating electrodes. Since cutouts andprotrusions can determine the tilt directions of the liquid crystalmolecules, the tilt directions can be distributed in various directionsby using the cutouts and the protrusions, thereby widening the referenceviewing angle.

SUMMARY

In a case of providing a plurality of branch electrodes by formingminute slits in a pixel electrode, a response speed of liquid crystalmolecules is reduced due to the relationship with liquid crystal controlpower other than the minute slits of the liquid crystal molecules, andthus texture is displayed for a period of time. Accordingly, the portionat which the texture is displayed is covered by a light blocking memberor the luminance of the portion at which the texture is displayed isreduced, thereby decreasing transmittance. Further, the transmittance isreduced due to the minute slits and the pattern of a pixel electrodeconnected to the minute slits.

In addition, since the size of one pixel is reduced as the LCD has ahigher resolution, the minute slits and the texture or the pattern ofthe pixel electrode connected to the minute slits are increasedcomparatively with the pixel area. Accordingly, the transmittance issignificantly reduced in a high resolution LCD.

The invention has been made in an effort to provide an LCD having theadvantage of being capable of improving transmittance. Further, theinvention has been made in an effort to provide an LCD having theadvantage of being capable of preventing a problem caused bytransmittance reduction even where the size of a pixel is reduced as theLCD has a higher resolution.

An exemplary embodiment of the invention provides an LCD including afirst insulation substrate, a gate line, a data line configured to crossthe gate line while being insulated therefrom, a thin film transistor(“TFT”) connected to the gate line and the data line, a pixel electrodeconfigured to include a first subpixel electrode connected to the TFTand a second subpixel electrode, a second insulation substrateconfigured to face the first insulation substrate, a common electrodedisposed on the second insulation substrate, and a liquid crystal layerdisposed between the first insulation substrate and the secondinsulation substrate to include a plurality of liquid crystal molecules,where each of the first subpixel electrode and the second subpixelelectrode includes one unit pixel electrode including a plurality ofminute branches that is extended from one horizontal stem and onevertical stem.

In an exemplary embodiment, the unit pixel electrode may have twodomains having different alignment directions of liquid crystalmolecules.

In an exemplary embodiment, a region at which the first subpixelelectrode is disposed may be a first subpixel area and a region at whichthe second subpixel electrode is disposed is a second subpixel area, thevertical stem may be disposed to be adjacent to one vertical side of thefirst subpixel area and the second subpixel area, one end of thehorizontal stem may be connected to a center of the vertical stem, andthe minute branches may be disposed to obliquely extend from thevertical stem and the horizontal stem toward the horizontal stem.

In an exemplary embodiment, the first subpixel electrode may have astructure in which the vertical stem is disposed at a right side and thehorizontal stem is extended from the right side to a left side, and theminute branches may be extended in an upper right direction or in alower right direction. The second subpixel electrode may have astructure in which the vertical stem is disposed at the left side andthe horizontal stem is extended from the left side to the right side,and the minute branch may be extended in an upper left direction or in alower left direction.

In an exemplary embodiment, a width of each of the first subpixelelectrode and the second subpixel electrode may be equal to or less thanabout 140 micrometers (μm).

In an exemplary embodiment, a width of each of the vertical stem or thehorizontal stem may be equal to or less than about 25 μm.

In an exemplary embodiment, the LCD may further include a third subpixelelectrode configured to be adjacent to a left side or a right side ofthe first subpixel electrode, and a fourth subpixel electrode configuredto be adjacent to a left side or a right side of the second subpixelelectrode, where the third subpixel electrode and the first subpixelelectrode have a facing structure, and the fourth subpixel electrode andthe second subpixel electrode have a facing structure.

In an exemplary embodiment, the LCD may further include a shieldingelectrode disposed between adjacent subpixel electrodes, above the dataline, and the shielding electrode may be disposed at a same layer as thesubpixel electrode.

In an exemplary embodiment, the LCD may further include a shieldingelectrode disposed between adjacent subpixel electrodes, above the dataline, and the shielding electrode may be disposed at a layer that islower than that of the subpixel electrode so as to partially overlap thesubpixel electrode.

In an exemplary embodiment, alignment direction of the liquid crystalmolecules which are aligned by the first subpixel electrode and thethird subpixel electrode adjacent thereto may be the same, and alignmentdirection of the liquid crystal molecules which are aligned by the bythe second subpixel electrode and the fourth subpixel electrode adjacentthereto may be the same.

In an exemplary embodiment, the LCD may further include a third subpixelelectrode configured to be adjacent to a left side or a right side ofthe first subpixel electrode, and a fourth subpixel electrode configuredto be adjacent to a left side or a right side of the second subpixelelectrode, and the third subpixel electrode and the first subpixelelectrode have a same directional structure, and the fourth subpixelelectrode and the second subpixel electrode have a same directionalstructure.

In an exemplary embodiment, the LCD may further include avoltage-dividing reference line extending in a direction of the dataline, so as to include a horizontal portion and a vertical portion.

In an exemplary embodiment, the vertical portion of the voltage-dividingreference line may be disposed to overlap the first subpixel electrodeand the vertical stem of the second subpixel electrode.

In an exemplary embodiment, the horizontal portion of thevoltage-dividing reference line may be overlapped with horizontal sidesof the first subpixel area and the second subpixel area, and thus may beoverlapped with one horizontal end of the minute branches of the firstsubpixel electrode and the second subpixel electrode.

In an exemplary embodiment, a TFT disposed between a TFT forming regionprovided between the first subpixel area and the second subpixel areamay include a first TFT connected to the gate line, the data line, andthe first subpixel electrode, a second TFT connected to the gate line,the data line, and the second subpixel electrode, and a third TFTconnected to the gate line, the voltage-dividing reference line, and thesecond subpixel electrode.

In an exemplary embodiment, a TFT disposed between a TFT forming regionprovided between the first subpixel area and the second subpixel areamay include a first TFT connected to the gate line, the data line, andthe first subpixel electrode, and a second TFT connected to the gateline, the data line, and the second subpixel electrode.

In an exemplary embodiment, the LCD may further include a color filterdisposed on the first insulation substrate or the second insulationsubstrate, and a light blocking member disposed on the first insulationsubstrate or the second insulation substrate.

In an exemplary embodiment, the light blocking member may be provided inan extending direction of the gate line.

In an exemplary embodiment, the LCD may be a curved LCD.

In accordance with the LCD according to the exemplary embodiment of theinvention, it is possible to eliminate display quality deteriorationcaused by transmittance reduction that is generated by a portion atwhich texture is generated, and a pattern of the pixel electrode in theLCD includes a pattern of the minute electrode. Further, even when theLCD has a high resolution, no display quality deterioration is generatedby the transmittance reduction. In addition, the exemplary embodiment ofthe invention may be applied to a flat LCD as well as the curved LCD.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary embodiments, advantages and features ofthis disclosure will become more apparent by describing in furtherdetail exemplary embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a schematic diagram of a pixel according to an exemplaryembodiment of the invention;

FIG. 2 is a cross-sectional view taken along a line II-II of the pixelaccording to the exemplary embodiment of FIG. 1;

FIGS. 3 to 5 are stepwise processing views illustrating the pixelaccording to the exemplary embodiment of FIG. 1;

FIG. 6 illustrates a relationship between the size of a pixel andtexture generation;

FIG. 7 illustrates texture generated in an LCD;

FIG. 8 is a cross-sectional view to explain the reason that texture isgenerated as shown in FIGS. 6 and 7;

FIG. 9 illustrates transmittance of a pixel according to an experimentalexample and a comparative example;

FIGS. 10 and 11 illustrate a structure of adjacent pixel electrodesaccording to an exemplary embodiment of the invention;

FIGS. 12 and 13 are cross-sectional views illustrating a region of apixel according to exemplary embodiments of the invention;

FIGS. 14 to 17 are equivalent circuit diagrams illustrating a pixelaccording to exemplary embodiments of the invention;

FIG. 18 is a schematic diagram of a pixel according to the exemplaryembodiment of FIG. 17;

FIG. 19 is a plan view of a pixel according to the exemplary embodimentof FIG. 18;

FIG. 20 is an equivalent circuit diagram illustrating an exemplaryembodiment of a pixel according to the invention; and

FIG. 21 illustrates a process for providing a pretilt to liquid crystalmolecules by using prepolymers that are polymerized by light such asultraviolet rays.

DETAILED DESCRIPTION

The invention will be described more fully hereinafter with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. As those skilled in the art would realize, thedescribed embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the invention.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

The structure of a pixel of a liquid crystal display (“LCD”) accordingto an exemplary embodiment of the invention will now be described indetail with reference to FIGS. 1 and 2.

FIG. 1 is a schematic diagram of a pixel according to an exemplaryembodiment of the invention, and FIG. 2 is a cross-sectional view takenalong a line II-II of the pixel according to the exemplary embodiment ofFIG. 1.

Referring to FIGS. 1 and 2, a gate conductor including a gate line 121and storage electrode lines 131 and 132 is disposed on a firstinsulation substrate 110 that includes transparent glass or plastic. Thegate line 121 includes gate electrodes 124 a, 124 b, and 124 c, and awide gate pad (not illustrated) for contact with another layer or anexternal driving circuit.

In an exemplary embodiment, the gate line 121 and the storage electrodelines 131 and 132 may include an aluminum-based metal, such as, aluminum(Al) or an aluminum alloy, a silver-based metal such as silver (Ag) or asilver alloy, a copper-based metal such as copper (Cu) or a copperalloy, a molybdenum-based metal such as molybdenum (Mo) or a molybdenumalloy, chromium (Cr), tantalum (Ta), and titanium (Ti). In an exemplaryembodiment, the gate line 121 may have a multilayered structureincluding at least two conductive layers having different physicalproperties.

The gate line 121 is disposed to traverse a pixel area in an extendingdirection of a row. A pair of subpixel electrodes for displayingdifferent grays is disposed at opposite ends of the gate line 121. Inthe exemplary embodiment of FIG. 1, the first subpixel electrode 191 afor displaying a high gray is disposed above the gate line 121, and thesecond subpixel electrode 191 b for displaying a low gray is disposedbelow the gate line 121.

In an exemplary embodiment, the storage electrode lines 131 and 132include the same material as the gate line 121, and may be provided byusing the same process as that of the gate line 121.

In an exemplary embodiment, the first storage electrode line 131disposed above the gate line 121 may have a quadrangular shape so as tosurround the first subpixel electrode 191 a, for example. An uppermostside of the quadrangular shaped first storage electrode line 131 mayhorizontally extend out of one pixel area so as to be connected toanother layer or an external driving circuit. Further, the quadrangularshaped first storage electrode line 131 has an extending structureincluding a left vertical side thereof that is downwardly extended to afirst contact hole 185 a. This extending structure may not be includedaccording to another exemplary embodiment.

The second storage electrode line 132 disposed below the gate line 121includes a pair of horizontal portions and one vertical portion thatconnects the pair of horizontal portions at edges thereof. Further, thesecond storage electrode line 132 has an extending structure extendingupwardly from the horizontal portion to a second contact hole 185 b. Inanother exemplary embodiment, this extending structure may not beincluded.

Shapes of the storage electrode lines 131 and 132 are described andillustrated in the above exemplary embodiment, but are not limitedthereto, and the storage electrode lines 131 and 132 may have any shapefor performing the same function without being limited thereto.

A gate insulating layer 140 is disposed on the gate conductor to coverthe gate conductor. A conduct hole is defined in a portion of the gateconductor which corresponds to the gate pad (not illustrated) to exposethe gate pad. The portions of the gate conductor other than the conducthole may be covered by the gate insulating layer 140. In an exemplaryembodiment, the gate insulating layer 140 may include a materialincluding silicon oxide or silicon nitride, for example.

A semiconductor layer including a first semiconductor layer 154 a, asecond semiconductor layer 154 b, and a third semiconductor layer 154 cis disposed on the gate insulating layer 140. The semiconductor layersother than the first semiconductor layer 154 a, the second semiconductorlayer 154 b, and the third semiconductor layer 154 c are disposed belowthe region at which a data conductor including a data line 171, adivided reference voltage line 172, a source electrode 173, and a drainelectrode 175 is disposed. This structure is provided in the case that asemiconductor layer is etched together with a data conductor when thedata conductor is etched, and the first semiconductor layer 154 a, thesecond semiconductor layer 154 b, and the third semiconductor layer 154c defining a channel of a thin film transistor (“TFT”) are disposed tocorrespond to a photoresist corresponding to a transflective region or aslit region on a mask.

In an exemplary embodiment, the semiconductor layer may include anamorphous silicon semiconductor, an oxide semiconductor, or apolycrystalline semiconductor, for example.

A plurality of ohmic contacts (not illustrated) may be disposed on thesemiconductors other than the first semiconductor layer 154 a, thesecond semiconductor layer 154 b, and the third semiconductor layer 154c, and may be omitted when the semiconductor layer includes an oxidesemiconductor.

The data conductor including the data line 171, the divided referencevoltage line 172, the source electrode 173, and the drain electrode 175is disposed on the ohmic contacts. This data conductor will be describedin more detail as follows.

The data conductor includes a data line 171, a first source electrode173 a, a second source electrode 173 b, a third source electrode 173 c,a first drain electrode 175 a, a second drain electrode 175 b, a thirddrain electrode 175 c, and a divided reference voltage line 172.

In an exemplary embodiment, the data conductor may include analuminum-based metal such as aluminum (Al) or an aluminum alloy, asilver-based metal such as silver (Ag) or a silver alloy, a copper-basedmetal such as copper (Cu) or a copper alloy, a molybdenum-based metalsuch as molybdenum (Mo) or a molybdenum alloy, chromium (Cr), tantalum(Ta), and titanium (Ti). In an exemplary embodiment, the data conductormay have a multilayered structure including at least two conductivelayers having different physical properties.

The data line 171 is extended in an extending direction of rows on onepixel area, and includes a first source electrode 173 a and a secondsource electrode 173 b. The first source electrode 173 a and the secondsource electrode 173 b may have a U-shape, but the invention is notlimited thereto.

The data line 171 includes a wide data pad (not illustrated) forconnection with another layer or an external driving circuit.

The first drain electrode 175 a is disposed to face the first sourceelectrode 173 a and has, for example, an I-shape corresponding to theU-shaped first source electrode 173 a, and includes a widely expandedregion that is connected to the first subpixel electrode 191 a.

Similarly, the second drain electrode 175 b is disposed to face thesecond source electrode 173 b and has, e.g., an I-shape corresponding tothe U-shaped second source electrode 173 b, and includes a widelyexpanded region that is connected to the second subpixel electrode 191b.

The third source electrode 173 c is provided to extend from one surfaceof the second drain electrode 175 b. As illustrated in FIG. 1, thesecond drain electrode 175 b is extended to form an expanded region, andis extended again from the expanded region to constitute the thirdsource electrode 173 c.

The divided reference voltage line 172 is extended in an extendingdirection of rows, but is bent and extended differently from the dataline 171, and includes a third source electrode 173 c and a third drainelectrode 175 c constituting a TFT.

The divided reference voltage line 172 includes a plurality ofhorizontal portions and a plurality of vertical portions which connectthe horizontal portions. Specifically, the divided reference voltageline 172 includes horizontal portions and vertical portions such thatthe vertical portions connect the horizontal portions with each other atone end of the horizontal portions which are parallel. A structure ofthe divided reference voltage line 172 will be described in more detail.The divided reference voltage line 172 is roughly divided into threeareas. Specifically, the divided reference voltage line 172 is roughlydivided into a high gray subpixel area in which the first subpixelelectrode 191 a for displaying a high gray is disposed, a low graysubpixel area in which the second subpixel electrode 191 b fordisplaying a low gray is disposed, and a TFT forming area disposedbetween the two subpixel areas in which three TFTs are disposed.

The divided reference voltage line 172 disposed in the high graysubpixel area has an inverse angulated

-shaped structure, includes a pair of horizontal portions and onevertical portion which connects the horizontal portions, and is disposedalong an outer circumference of the high gray subpixel area. The dividedreference voltage line 172 disposed in the low gray subpixel area has anangulated

-shaped structure, includes a pair of horizontal portions and onevertical portion for the connecting the horizontal portions, and isdisposed at an outer circumference of the low gray subpixel area.Finally, the divided reference voltage line 172 disposed in the TFTforming area includes the angulated

-shaped structure, a vertical portion for connecting the inverseangulated

-shaped structure, and the third drain electrode 175 c. In this case,the vertical portion is disposed at a right side of the TFT formingarea, and the third drain electrode 175 c is extended from a horizontalportion disposed below the inverse angulated

-shaped structure. The detailed structure of the divided referencevoltage line 172 may be variously changed according to exemplaryembodiments.

The data conductor, the ohmic contacts, and the semiconductor layer maybe simultaneously provided by using one mask.

The first gate electrode 124 a, the first source electrode 173 a, andthe first drain electrode 175 a constitute a first TFT Qa (refer to FIG.14) together with the first semiconductor layer 154 a, and a channel ofthe first TFT is defined at the first semiconductor layer 154 a disposedbetween the first source electrode 173 a and the first drain electrode175 a. Similarly, the second gate electrode 124 b, the second sourceelectrode 173 b, and the second drain electrode 175 b constitute asecond TFT Qb (refer to FIG. 14) together with the second semiconductorlayer 154 b, and a channel of the second thin film layer is defined atthe second semiconductor layer 154 b disposed between the second sourceelectrode 173 b and the second drain electrode 175 b. The third gateelectrode 124 c, the third source electrode 173 c, and the third drainelectrode 175 c constitute a third TFT Qc (refer to FIG. 14) togetherwith the third semiconductor layer 154 c, and a channel of the thirdthin film layer is defined at the third semiconductor layer 154 cdisposed between the third source electrode 173 c and the third drainelectrode 175 c.

A first passivation layer 180 p is disposed on the data conductor andthe exposed semiconductor layers 154 a, 154 b, and 154 c. In anexemplary embodiment, the first passivation layer 180 p may include asilicon nitride, a silicon oxide, or the like that is used to form aninorganic insulating layer, for example. In an exemplary embodiment, asecond passivation layer 180 q is disposed on the first passivationlayer 180 p, and may include an organic material unlike the firstpassivation layer 180 p, for example. According to another exemplaryembodiment, one of the first passivation layer 180 p and the secondpassivation layer 180 q may be omitted. According to another exemplaryembodiment, a color filter may be disposed at the position of the secondpassivation layer 180 q. In this case, the first passivation layer 180 pmay serve to prevent a pigment of the color filter from flowing into theexposed semiconductor layers 154 a, 154 b, and 154 c. Even when thecolor filter is disposed, the second passivation layer 180 q may beprovided to cover the color filter.

In the case where the second passivation layer 180 q is the colorfilter, and where the color filter is disposed at an additionalposition, the second passivation layer 180 q may intrinsically displayany one primary color, and examples of the primary colors may includethree primary colors such as red, green, and blue, or yellow, cyan, andmagenta, or the like. Although not illustrated, a color filter mayfurther include a color filter for displaying a mixed color of theprimary colors or white in addition to the primary colors.

A first contact hole 185 a and a second contact hole 185 b are definedin the first and second passivation layers 180 p and 180 q to expose thefirst and second drain electrodes 175 a and 175 b, respectively.

A pixel electrode 191 and a shielding electrode 199 are disposed on thesecond passivation layer 180 q.

The pixel electrode 191 includes the first subpixel electrode 191 a andthe second subpixel electrode 191 b, which interpose the gate line 121therebetween to be separated from and to neighbor each other in thecolumn direction. The first subpixel electrode 191 a is disposed in thehigh gray subpixel area, and the second subpixel electrode 191 b isdisposed in the low gray subpixel area.

Each of the first subpixel electrode 191 a and the second subpixelelectrode 191 b includes one horizontal stem 193 a and 193 b and onevertical stem 194 a and 194 b, and further includes a plurality ofminute branches 197 a and 197 b which is obliquely extended therefrom.

In this case, the minute branches 197 a are arranged in two directions,and thus the first subpixel electrode 191 a or the second subpixelelectrode 191 b has two domains. The structure of the first subpixelelectrode 191 a or the second subpixel electrode 191 b including twodomains is referred to as one unit pixel electrode.

As shown in FIG. 1, the low gray subpixel area is about 1.5 times toabout 2.5 times larger than the high gray subpixel area. As such,although the two subpixel areas are different from each other, onehorizontal stem and one vertical stem are provided in each of the twosubpixel areas according to the exemplary embodiment of the invention.In other words, according to an exemplary embodiment of the invention,the first and second subpixel electrodes 191 a and 191 b respectivelyinclude the minute branches 197 a and 197 b, each of which is arrangedin two directions, and thus each includes two domains. These two domainsare fewer than the four domains of one general subpixel electrode. Theimproved transmittance due to using the reduced number of domains willbe described later with reference to FIGS. 6 to 9.

Extending directions of the minute branches 197 a in the high graysubpixel electrode are different from those of the minute branches 197 bin the low gray subpixel electrode. Specifically, in the high graysubpixel electrode 191 a, the vertical stem 194 a is disposed at a rightside, the horizontal stems 193 a are extended from the right side to aleft side, and the minute branches 197 a are extended in an upper rightdirection or in a lower right direction. In contrast, in the low graysubpixel electrode 191 b, the vertical stem 194 b is disposed at theleft side, the horizontal stem 193 b is extended from the left side tothe right side, and the minute branches 197 b are extended in an upperleft direction or in a lower left direction.

The vertical stems 194 a and 194 b of the first subpixel electrode 191 aand the second subpixel electrode 191 b, respectively, are overlappedwith the vertical portions of the divided reference voltage line 172,and the horizontal stems 193 a and 193 b thereof are not overlapped withthe horizontal portions of the divided reference voltage line 172.

Although the pixel size gets smaller in a higher resolution LCD, apredetermined number of minute branches or stems may be provided to havea predetermined size. In the exemplary embodiment of the invention, onestem is provided in one subpixel area, and thus the texture generated inthe pixel area can be controlled, display errors can be reduced, andlight transmittance can be improved.

Further, in the case of providing a curved display device, it ispossible to reduce display errors caused by misalignment between upperand lower substrates through the pixel electrode that is extended fromthe horizontal stem. As a result, the LCD according to the exemplaryembodiment of the invention can be applied to a curved LCD having acurved structure as well as a general LCD having a flat structure.Particularly, the LCD according to the exemplary embodiment of theinvention has relatively further improved characteristics in the curvedstructure compared to other pixel structures.

The shielding electrode 199 includes vertical portions 196 that areextended along the data line 171, and one or more horizontal portions198 that interconnect the adjacent vertical portions 196. The horizontalportion 198 of the shielding electrode 199 may include an expandedregion at the center thereof. The shielding electrode 199 may receivethe same voltage as a common electrode 270 (refer to FIG. 8).Accordingly, no electric field is generated between the shieldingelectrode 199 and the common electrode 270, and thus liquid crystalmolecules interposed therebetween are not aligned. As a result, theliquid crystal molecules interposed between the shielding electrode 199and the common electrode 270 are in a black state. As such, in the casethat a polarizer (not illustrated) is attached such that a state inwhich no electric field is applied to the liquid crystal molecules isdisplayed as black, the corresponding region can be covered by theliquid crystal molecules themselves to be invisible without using anadditional light blocking member. Accordingly, in the display deviceaccording to the exemplary embodiment of the invention, a light blockingmember disposed on a second insulation substrate to extend in anextending direction of columns (an extending direction of the data line)can be omitted at some portions at least, thereby improvingtransmittance. In this case, the light blocking member may be providedin the extending direction of the gate line, and may be disposed on afirst or second insulation substrate.

In an exemplary embodiment, the pixel electrode 191 and the shieldingelectrode 199 may include a transparent material such as indium tinoxide (“ITO”) and indium zinc oxide (“IZO”).

An upper display panel will now be described. Although not illustrated,the upper display panel is a constituent element that is required toaccommodate a liquid crystal layer in the LCD. However, in an LCDincluding an additional structure for accommodating the liquid crystallayer, the upper display panel may be omitted.

The upper display panel included in an LCD will be described.

A light blocking member (not illustrated) is disposed on a secondinsulation substrate (not illustrated) disposed to face a firstinsulation substrate 110 including transparent glass, plastic, or thelike. The light blocking member is also referred to as a black matrixand prevents light leakage. The light blocking member which is describedto be disposed in the upper display panel may be disposed in a lowerdisplay panel according to another exemplary embodiment.

In the exemplary embodiment, the light blocking member may be disposedto extend in a column direction extending along the data line 171. Thisis because no light blocking member is additionally required since theliquid crystal layer itself displays black at the region provided alongthe data line 171 by the action of the shielding electrode 199. However,to accomplish a stronger light blocking characteristic, a light blockingmember may be disposed along the data line 171. In this case, althoughthe light blocking member is disposed along the data line 171, thislight blocking member may have a width that is narrower than that of ageneral light blocking member. Accordingly, the transmittance can beimproved.

A plurality of color filters (not illustrated) is also disposed on thesecond insulation substrate.

An overcoat (not illustrated) may be disposed on the color filters andthe light blocking member. The overcoat may include an organic insulatorin order to remove steps caused by the color filters and the lightblocking member and to provide a flat surface. In another exemplaryembodiment, the overcoat may be omitted.

A common electrode 270 (refer to FIG. 8) is disposed on the overcoat. Inan exemplary embodiment, the common electrode 270 may include the samematerial as that of the pixel electrode 191, and may be provided in aflat surface type to receive a common voltage, for example.

Further, an alignment layer (not illustrated) may be disposed inside thepixel electrode 191 and the common electrode 270.

A liquid crystal layer (not illustrated) may be disposed inside thealignment layer between the lower display panel and the upper displaypanel. The liquid crystal layer has negative dielectric anisotropy, andliquid crystal molecules of the liquid crystal layer are aligned suchthat long axes thereof are perpendicular to surfaces of the upper andlower display panels in a state in which no electric field is generated.

The first and second subpixel electrodes 191 a and 191 b, to which thedata voltage is applied, generate an electric field along with thecommon electrode 270 (refer to FIG. 8) of the upper display panel 200(refer to FIG. 8), thereby determining the alignment directions of theliquid crystal molecules of the liquid crystal layer interposed betweenthe two electrodes 191 and 270. Depending on the determined directionsof the liquid crystal molecules, a phase difference of light passingthrough the liquid crystal layer is varied, and thus an amount of lightpassing through the polarizer is adjusted to control display luminance.

In the above exemplary embodiments, the pixel structure of the LCD inwhich one horizontal stem 193 b and one vertical stem 194 b are providedeven in the low gray subpixel area was described.

Hereinafter, a detailed structure thereof will be described withreference to FIGS. 3 to 5.

FIGS. 3 to 5 are stepwise processing views illustrating the pixelaccording to the exemplary embodiment of FIG. 1.

First, a structure of the gate conductor is illustrated in FIG. 3.

Referring to FIG. 3, the gate conductor includes the gate line 121 andthe storage electrode lines 131 and 132. A gate conductor material isstacked on an insulation substrate, and then a photoresist pattern isdisposed thereon in order to be etched to form the gate conductor.

The gate line 121 is disposed to traverse a pixel area in an extendingdirection of rows. The first storage electrode line 131 has aquadrangular structure above the gate line 121, and the second storageelectrode line 132 has an angulated

-shaped structure.

The gate line 121 has a partially bent structure that upwardly anddownwardly protrudes at portions at which the first to third gateelectrodes 124 a, 124 b, and 124 c are disposed.

An uppermost side of the quadrangular shaped first storage electrodeline 131 may be out of one pixel area so as to horizontally extend to beconnected to another layer or an external driving circuit. Further, thequadrangular shaped first storage electrode line 131 has an extendingstructure, including a left vertical side thereof that is downwardlyextended to a first contact hole 185 a (refer to FIG. 1). This extendingstructure may not be included according to another exemplary embodiment.

The angulated

-shaped structure of the second storage electrode line 132 includes apair of horizontal portions and one vertical portion that connects thepair of horizontal portions at edges thereof. Further, the secondstorage electrode line 132 has an extending structure extending upwardlyfrom the horizontal portion to a second contact hole 185 b (refer toFIG. 1). This extending structure may not be included according toanother exemplary embodiment.

After the gate conductor illustrated in FIG. 3 is provided, a gateinsulating layer material, a semiconductor material, and a dataconductor material are sequentially stacked. Next, the semiconductormaterial and the data conductor material are etched by using one mask,to form a structure illustrated in FIG. 4. According to anotherexemplary embodiment, an ohmic contact layer may be further disposedbetween the semiconductor material and the data conductor material tohave the same shape as that of the data conductor.

Referring to FIG. 4, the data conductor includes a data line 171, afirst source electrode 173 a, a second source electrode 173 b, a thirdsource electrode 173 c, a first drain electrode 175 a, a second drainelectrode 175 b, a third drain electrode 175 c, and a divided referencevoltage line 172.

The data line 171 is extended in an extending direction of rows on onepixel area, and includes a first source electrode 173 a and a secondsource electrode 173 b. Each of the first source electrode 173 a and thesecond source electrode 173 b are disposed to have a U-shape.Specifically, the first source electrode 173 a has a U-shape with anupper side open, and the second source electrode 173 b has a U-shapewith a right side open.

The first drain electrode 175 a is disposed to face the first sourceelectrode 173 a and to have an I-shape corresponding to the U-shapedfirst source electrode 173 a, and includes a widely expanded region thatis connected to the first subpixel electrode 191 a.

The second drain electrode 175 b is disposed to face the second sourceelectrode 173 b and to have an I-shape corresponding to the U-shapedsecond source electrode 173 b, and includes a widely expanded regionthat is connected to the second subpixel electrode 191 b.

The third source electrode 173 c is provided by extending from a surfaceof the second drain electrode 175 b and then extending from a regionextended from the second drain electrode 175 b.

The divided reference voltage line 172 is extended in an extendingdirection of rows, but is bent and extended unlike the data line 171 andthird drain electrode 175 c. The divided reference voltage line 172includes horizontal portions and vertical portions such that thevertical portions connect the horizontal portions which are parallelwith each other at one end of the horizontal portions. As illustrated inFIG. 4, the divided reference voltage line 172 is roughly divided intothree areas. The divided reference voltage line 172 disposed in the highgray subpixel area has an inverse angulated

-shaped structure, includes a pair of horizontal portions and onevertical portion which connects the horizontal portions, and is disposedalong an outer circumference of the high gray subpixel area. Further,the divided reference voltage line 172 disposed in the low gray subpixelarea has an angulated

-shaped structure, includes a pair of horizontal portions and onevertical portion which connects the horizontal portions, and is disposedalong an outer circumference of the low gray subpixel area. Finally, thedivided reference voltage line 172 disposed in the TFT forming areaincludes a vertical portion for connecting the inverse angulated

-shaped structure and the angulated

-shaped structure, and the third drain electrode 175 c. In this case,the vertical portion is disposed at a right side of the TFT formingarea, and the third drain electrode 175 c is extended from a horizontalportion disposed below the inverse angulated

-shaped structure.

When the data conductor is etched, the semiconductor layer is alsoetched, and most parts of the semiconductor layer are disposed below thedata conductor. However, the first semiconductor layer 154 a, the secondsemiconductor layer 154 b, and the third semiconductor layer 154 c atwhich channels of the thin film layers are respectively defined areexposed thereabove. A slit mask or a transflective mask is employed toform the first semiconductor layer 154 a, the second semiconductor layer154 b, and the third semiconductor layer 154 c, which are exposed.

In other words, when the data conductor is provided, the slit mask orthe transflective mask is employed. In this case, the slit mask or thetransflective mask includes a transmissive region, a blocking region,and a transflective region. A transflective layer or slits are providedat the transflective region. Photoresist provided as the transmissiveregion and the blocking region is used to form most patterns of the dataconductor, and the first semiconductor layer 154 a, the secondsemiconductor layer 154 b, and the third semiconductor layer 154 c, asthe remaining regions, are provided by the photoresist provided throughthe transflective region. The patterns of the data conductor, the firstsemiconductor layer 154 a, the second semiconductor layer 154 b, and thethird semiconductor layer 154 c are provided by using one mask and oneprocess.

Next, the first and second passivation layers 180 p and 180 q areprovided to cover the data conductor and the exposed semiconductors (thefirst semiconductor layer 154 a, the second semiconductor layer 154 b,and the third semiconductor layer 154 c) and a gate insulating layer,thereon. Next, a first contact hole 185 a and a second contact hole 185b are respectively defined to expose the first drain electrode 175 a andthe second drain electrode 175 b.

Next, as illustrated in FIG. 5, the pixel electrode 191 and theshielding electrode 199 are provided.

The pixel electrode 191 includes the first subpixel electrode 191 a andthe second subpixel electrode 191 b. The first subpixel electrode 191 ais disposed in the high gray subpixel area, and the second subpixelelectrode 19 ibis disposed in the low gray subpixel area.

The first subpixel electrode 191 a and the second subpixel electrode 191b respectively include one horizontal stem 193 a and 193 b and onevertical stem 194 a and 194 b, and further include a plurality of minutebranches 197 a and 197 b which is obliquely extended therefrom,respectively.

In this case, the minute branches 197 a are arranged in two directions,and thus the first subpixel electrode 191 a or the second subpixelelectrode 191 b has two domains. The structure of the first subpixelelectrode 191 a or the second subpixel electrode 191 b including twodomains is referred to as one unit pixel electrode.

The low gray subpixel area is about 1.5 times to about 2.5 times largerthan the high gray subpixel area. As such, although the two subpixelareas are different from each other, one horizontal stem and onevertical stem are provided in each of the two subpixel areas accordingto the exemplary embodiment of the invention. In other words, accordingto an exemplary embodiment of the invention, the first and secondsubpixel electrodes 191 a and 191 b respectively includes the minutebranches 197 a and 197 b, each of which is arranged in two directions,and thus each includes two domains. These two domains are fewer than thefour of the domains of one general subpixel electrode. The transmittanceimprovement caused by using the reduced number of domains will bedescribed later with reference to FIGS. 6 to 9.

The vertical stems 194 a and 194 b of the first subpixel electrode 191 aand the second subpixel electrode 191 b are overlapped with the verticalportions of the divided reference voltage line 172, and the horizontalstems 193 a and 193 b thereof are not overlapped with the horizontalportions of the divided reference voltage line 172.

Although the pixel size gets smaller in a higher resolution LCD, apredetermined number of minute branches or stems may be provided to havea predetermined size. In the exemplary embodiment of the invention, onestem is provided in one subpixel area, and thus the texture generated inthe pixel area can be controlled, display errors can be reduced, andlight transmittance can be improved.

Further, in the case of providing a curved display device, it ispossible to reduce display errors caused by misalignment between upperand lower substrates through the pixel electrode that is extended fromthe horizontal stem. As a result, the LCD according to the exemplaryembodiment of the invention can be applied to a curved LCD having acurved structure as well as a general LCD having a flat structure.Particularly, the LCD according to the exemplary embodiment of theinvention has relatively further improved characteristics in the curvedstructure compared to other pixel structures.

The shielding electrode 199 includes vertical portions 196 that areextended along the data line 171, and one or more horizontal portions198 that interconnect the adjacent vertical portions 196. The horizontalportion 198 of the shielding electrode 199 may include an expandedregion at the center thereof. The shielding electrode 199 may receivethe same voltage as a common electrode 270 (refer to FIG. 8).Accordingly, no electric field is generated between the shieldingelectrode 199 and the common electrode 270, and thus liquid crystalmolecules interposed therebetween are not aligned. As a result, theliquid crystal molecules interposed between the shielding electrode 199and the common electrode 270 are in a black state. As such, in the casethat a polarizer (not illustrated) is attached such that a state inwhich no electric field is applied to the liquid crystal molecules isdisplayed as black, the corresponding region can be covered by theliquid crystal molecules themselves to be invisible without using anadditional light blocking member. Accordingly, in the display deviceaccording to the exemplary embodiment of the invention, a light blockingmember disposed on a second insulation substrate to extend in the columndirection can be omitted at some portions at least, thereby improvingtransmittance.

In an exemplary embodiment, the pixel electrode 191 and the shieldingelectrode 199 may include a transparent material such as ITO and IZO.

Characteristics of an LCD having a structure provided as such will bedescribed with reference to FIGS. 6 to 9.

FIG. 6 illustrates a relationship between the size of a pixel andtexture generation.

Two pixels, each having different widths and textures, are illustratedin FIG. 6.

The left pixel illustrates a high gray subpixel electrode of a pixelincluded in an LCD having 46-inch full HD resolution (on the left) alongwith a photograph of texture (on the right). The left pixel has a widthof about 210 micrometers (μm), and one stem has a width of about 35 μm.Further, fourteen slits are provided by the minute branches. It is shownthat when the pixel having this structure is used, barely any texture isgenerated.

The right pixel illustrates a high gray subpixel electrode of a pixelincluded in an LCD having 55-inch full HD resolution (on the left) alongwith a photograph of texture (on the right). The right pixel has a widthof about 105 μm, and one stem has a width of about 18 μm. Further, sevenslits are provided by the minute branches. It is seen that when thepixel having this structure is used, a significant amount of texture isgenerated, thereby reducing the transmittance.

One reason that the transmittance is deteriorated by such texture isthat the space occupied by the pixel electrode is reduced as theresolution is increased. In addition, another reason is that a rate atwhich widths of the stems and/or the minute branches are reduced isrelatively smaller than a rate at which an area of the pixel is reduced.This is because the widths of the stems and/or the minute branches aredetermined by the resolution of a light exposer, and as the pattern ofthe pixel electrode is miniaturized, the resolution of the light exposerapproaches its limit.

Further, the structure of the pixel electrode used in FIG. 6 includestwo unit pixel electrodes each of which includes one horizontal stem,one vertical stem, and a plurality of minute branches, unlike in theexemplary embodiment of the invention. As a result, a connector may bedisposed to connect the two unit pixel electrodes, and the alignmentdirection of the liquid crystal molecules positioned around theconnector may be different from the alignment direction of the liquidcrystal molecules positioned at each domain. In FIG. 6, it can be seenthat no texture is generated in the left pixel having a large size,while the problem in the alignment of the liquid crystal moleculesaffects the domains in the right pixel.

As such, since one subpixel electrode includes a unit pixel electrodehaving two domains in a high resolution pixel having a small size, eachof the subpixel electrodes includes unit pixel electrodes having twodomains in the invention.

According to the experiment in FIG. 6, in the case the pixel electrodehas a width of about 105 μm when two unit pixel electrodes are used,texture is generated. However, in the case of 210 μm, no texture isgenerated. In consideration of another experiment, in the case that thepixel electrode has a width of 140 μm or less, it is possible to help toimprove display quality by using one unit pixel electrode to form onesubpixel electrode, as in the exemplary embodiment of the invention.

Further, in the case that the horizontal stem or vertical stem has awidth of 25 μm or less, it is possible to help to improve displayquality by using one unit pixel electrode to form one subpixelelectrode.

FIG. 7 also illustrates texture generated in a pixel of a 55-inch LCD,as shown in the right pixel of FIG. 6.

In FIG. 7, a structure in which the high gray subpixel electrodeincludes two unit pixel electrodes and the low gray subpixel electrodeincludes two unit pixel electrodes is illustrated.

As indicated by arrows in FIG. 7, it can be seen that texture isgenerated around a connector which connects the two unit pixelelectrodes. Accordingly, in the case of the pixel having a predeterminedsize level i.e., a width of 210 μm or less, it is possible to reduce thetexture by using one unit pixel electrode.

FIG. 8 illustrates the reason that texture is generated in a curved LCD.

FIG. 8 is a cross-sectional view of an LCD according to an embodiment,which will be described in brief.

In the lower display panel, the data line 171 is disposed in the lowersubstrate 110. Further, different color filters are separately disposedbased on the data line 171. Although an insulating layer and a wiringlayer may be disposed between the lower insulation substrate 110 and thedata line 171, they are omitted for the sake of brevity in thisillustration. The pixel electrode 191 may be disposed on the colorfilters 230. In the upper display panel, a light blocking member 220 isdisposed at a side of an upper insulation substrate 210. Further, anovercoat 250 is disposed to cover the light blocking member 220. Thecommon electrode 270 is disposed below the overcoat 250. A liquidcrystal layer having liquid crystal molecules 31 is disposed between theupper display panel and the lower display panel.

In the case that the LCD is provided as a curved type, curvatures of anupper substrate and a lower substrate are changed, alignment directionsof an upper group and a lower group of liquid crystal modules arepartially inverse to each other. These opposite alignments may be viewedas texture when generated at one domain. Accordingly, the curved LCD hasa higher possibility of generating texture than the flat LCD.Accordingly, as in the exemplary embodiment of the invention, thetexture can be reduced to improve transmittance by using one unit pixelelectrode to form each subpixel electrode.

FIG. 9 illustrates transmittance comparison between an experimentalexample in which one subpixel electrode is provided by using one unitpixel electrode and a comparative example in which one of two subpixelelectrodes includes two unit pixel electrodes.

FIG. 9 illustrates a portion of one display panel, specifically a firstpixel and a second pixel and a third pixel that are upwardly anddownwardly adjacent to the first pixel. That is, one pixel extends froma top black line to a bottom black line over a middle bold black line ineach picture. The adjacent pixels are illustrated at an upper side and alower side of the pixel. Specifically, one subpixel (high gray subpixel)of the pixel extends from the top black line to the middle bold blackline, and the other subpixel (low gray subpixel extends from the middlebold black line to the bottom black line). Further, in the left columnof FIG. 9, one subpixel includes one unit pixel electrode, and thus noblack line is displayed between the high gray subpixel area and the lowgray subpixel area. As a result, no luminance loss is generated.

In contrast, in the comparative example illustrated on the right side ofFIG. 9, the high gray subpixel electrode includes one unit pixelelectrode, while the low gray subpixel electrode includes two unit pixelelectrodes. Although the low gray subpixel electrode is larger than thehigh gray subpixel electrode, and thus the low gray subpixel electrodeincludes two unit pixel electrodes, a relative small amount of texturemay be generated. Accordingly, this case is selected as the comparativeexample. However, as illustrated on the right side of FIG. 9, a blackline is generated at the center of the low gray subpixel area of thecomparative example, thereby reducing the luminance. In this case, thecentral black line is generated between the two unit pixel electrodes.This central black line causes the luminance reduction, therebydeteriorating the display quality. Accordingly, the luminancecharacteristic of the experimental example can be more improved than thecomparative example.

In the above experimental example, it was described that thetransmittance can be improved by using one unit pixel electrode to formone subpixel electrode in the case of the pixel having a width of 140 μmor less, or the horizontal stem or the vertical stem having a width of25 μm or less.

Hereinafter, the arrangement between adjacent pixel electrodes will bedescribed.

FIGS. 10 and 11 illustrate a structure of adjacent pixel electrodesaccording to an exemplary embodiment of the invention.

First, FIG. 10 illustrates an arrangement relationship of one subpixelelectrode with another subpixel electrode that is adjacent thereto.

In the exemplary embodiment of FIG. 10, in a first subpixel electrodedisposed at a left side (n^(th)-column pixel), a vertical stem 194 isdisposed at the left side, and a horizontal stem 193 and minute branches197 are disposed to extend from the left side toward a right side. In asecond subpixel electrode disposed at the right side ((n+1)^(th)-columnpixel), a vertical stem 194-1 is disposed at the right side, and ahorizontal stem 193-1 and minute branches 197-1 are disposed to extendfrom the right side toward the left side. This structure is referred toas a facing structure.

According to embodiments, the second subpixel electrode disposed at theright side ((n+1)^(th)-column pixel) has a symmetrical structure withthe first subpixel electrode disposed at a left side (n^(th)-columnpixel). According to another exemplary embodiment, in the secondsubpixel electrode disposed at the right side ((n+1)^(th)-column pixel),a vertical stem may be disposed at the left side, and a horizontal stemand minute branches are disposed to extend from the left side toward theright side. This structure is referred to as a same-directionalstructure. Since the same-directional structure is provided by repeatingone pixel, no additional illustration thereof is provided

Similarly, FIG. 11 illustrates a structure of adjacent pixels in thecase of having the same facing structure as illustrated in FIG. 10.

The symbols “<” and “>” illustrated in FIG. 11 do not indicate astructure that substantially pertains to the pixel, but are added toclearly indicate the directions in which the subpixel electrodes areprovided.

As shown in FIG. 11, each subpixel electrode has the facing structure ofhorizontally adjacent pixels. However, as described above, all theadjacent subpixel electrodes may have the same-directional structure.

Hereinafter, exemplary embodiments according to layer positions of theshielding electrode 199 will be described with reference to FIGS. 12 and13.

FIGS. 12 and 13 are cross-sectional views illustrating a region of apixel according to exemplary embodiments of the invention.

In the exemplary embodiment of FIG. 12, pixel electrodes 191R and 191Land a shielding electrode 199 are provided in the same layer as in theexemplary embodiment of FIG. 1.

The structure of FIG. 12 will be described in brief.

A gate insulating layer 140 is covered on the lower insulation substrate110. The data line 171 is disposed on the gate insulating layer 140. Apassivation layer 180 is disposed on and to cover data line 171. Thepixel electrodes 191R and 191L and the shielding electrode 199 aredisposed on the passivation layer 180. The shielding electrode 199 isdisposed above the data line 171, and is provided along an extendingdirection of the data line 171. The right pixel electrode 191R isdisposed at a right side of the shielding electrode 199, and the leftpixel electrode 191L is disposed at a left side of the shieldingelectrode 199.

In the exemplary embodiment of FIG. 12, the pixel electrodes 191R and191L and the shielding electrode 199 are provided at the same layer, andthus a predetermined margin needs to be provided between the pixelelectrodes 191R and 191L and the shielding electrode 199 to preventshort-circuit therebetween. In other words, a predetermined distance isgenerally maintained between the left pixel electrode 191L and the rightpixel electrode 191R. Accordingly, although the alignment directions ofthe liquid crystal molecules positioned in adjacent pixel areas aredifferent from each other, the liquid crystal molecules are less likelyto affect each other. As a result, as shown in FIG. 12, although theliquid crystal molecules positioned in adjacent pixel areas are alignedin different directions, no problem is generated. In the exemplaryembodiment of FIG. 12, when the liquid crystal molecules positioned atthe adjacent pixel areas have the same alignment direction, no problemis generated either.

As illustrated in FIG. 13, the pixel electrodes 191R and 191L and theshielding electrode 199 are provided at different layers.

A structure illustrated in FIG. 13 will be described in brief.

A gate insulating layer 140 is coated on the lower insulation substrate110. The data 171 is disposed on the gate insulating layer 140. Thefirst passivation layer 180 p is disposed on and to cover the data line171. The shielding electrode 199 is disposed on the first passivationlayer 180 p. The shielding electrode 199 is disposed above the data line171, and is provided along an extending direction of the data line 171.The second passivation layer 180 q is disposed on and to cover theshielding electrode 199, and the pixel electrodes 191R and 191L aredisposed on the second passivation layer 180 q.

In the exemplary embodiment of FIG. 13, the pixel electrodes 191R and191L and the shielding electrode 199 are provided at different layers.In an exemplary embodiment, the shielding electrode 199 is provided at alayer that is lower than the pixel electrodes 191R and 191L. In thiscase, even when the pixel electrodes 191R and 191L are overlapped withthe shielding electrode 199, short-circuit is generated. Accordingly, adistance between the adjacent pixel electrodes can be reduced. As aresult, when liquid crystal molecules positioned at two adjacent pixelsare aligned in different directions, the liquid crystal molecules affecteach other, thereby generating texture. Accordingly, in the exemplaryembodiment of FIG. 13, the display quality can be improved by allowingthe liquid crystal molecules positioned at two adjacent pixels to bealigned in the same direction.

The exemplary embodiment of the invention is related to the structure ofthe pixel electrode, and thus other structures may be varied.Hereinafter, various kinds of pixels are illustrated through theequivalent circuit diagrams of the pixels of FIGS. 14 to 17 and 20.Hereinafter, structures for differently adjusting voltage levels of twosubpixel electrodes in various ways will be described through simplecircuit diagrams.

First, an exemplary embodiment of FIG. 14 will be described.

In FIG. 14, a circuit diagram of a pixel which applies different levelsof voltages to two subpixel electrodes by using a reference voltage lineRL described above is illustrated.

In FIG. 14, a high gray subpixel and a low gray subpixel arerespectively indicated by PXa and PXb.

Referring to FIG. 14, an LCD according to an exemplary embodiment of theinvention includes signal lines including the gate line GL, the dataline DL, a reference voltage line RL transferring a reference voltage,and the like, and the pixel PX connected thereto.

Each pixel includes first and second subpixels PXa and PXb. The firstsubpixel PXa includes the first switching element Qa and the firstliquid crystal capacitor Clca, and the second subpixel PXb includes thesecond and third switching elements Qb and Qc and the second liquidcrystal capacitor Clcb. The first and second switching elements Qa andQb are each connected to the gate line GL and the data line DL, and thethird switching element Qc is connected to the output terminal of thesecond switching element Qb and the reference voltage line RL. Theoutput terminal of the first switching element Qa is connected to thefirst liquid crystal capacitor Clca, and the output terminal of thesecond switching element Qb is connected to the second input liquidcrystal capacitor Clcb and the input terminal of the third switchingelement Qc. The control terminal of the third switching element Qc isconnected to the gate line GL, an input terminal thereof is connected tothe second liquid crystal capacitor Clcb, and the output terminalthereof is connected to the reference voltage line RL.

An operation of the pixel PX shown in FIG. 14 will now be described.When a gate-on voltage Von is first applied to the gate line GL, thefirst, second, and third switching elements Qa, Qb, and Qc connectedthereto are turned on. Accordingly, the data voltage applied to the dataline DL is applied to the first liquid crystal capacitor Clca and thesecond liquid crystal capacitor Clcb, respectively, through the firstswitching element Qa and the second switching element Qb, which areturned on, and thus the first liquid crystal capacitor Clca and thesecond liquid crystal capacitor Clcb are charged in proportion to adifference between the data voltage and the common voltage. In thiscase, the same data voltage is transferred to the first liquid crystalcapacitor Clca and the second liquid crystal capacitor Clcb throughfirst and second switching elements Qa and Qb, but the charging voltageof the second liquid crystal capacitor Clcb is divided through the thirdswitching element Qc. As a result, the charging voltage of the secondliquid crystal capacitor Clcb is smaller than that of the first liquidcrystal capacitor Clca, and thus the luminance of the two subpixels PXaand Pxb may be different. Accordingly, by appropriately adjusting thevoltage of the first liquid crystal capacitor Clca and the voltage ofthe second liquid crystal capacitor Clcb, an image viewed from the sidecan be controlled to approach an image viewed from the front as closelyas possible, thereby improving side visibility.

However, the pixel structure of the LCD according to the exemplaryembodiment of the invention may be varied without being limited to theexemplary embodiment of FIG. 14.

Hereinafter, an exemplary embodiment of FIG. 15 will be described.

An LCD according to the exemplary embodiment of the invention includessignal lines including a plurality of gate lines GL, a plurality of datalines DL, and a plurality of storage electrode lines SL, and a pluralityof pixels PX connected thereto. Each pixel PX includes a pair of firstand second subpixels PXa and PXb, a first subpixel electrode is providedin the first subpixel PXa, and a second subpixel electrode is providedin the second subpixel PXb.

The LCD according to the exemplary embodiment of the invention includesa switching element Q coupled to the gate line GL and the data line DL,a first storage capacitor Csta and a first liquid crystal capacitor Clcathat are coupled to the switching element Q to be provided in the firstsubpixel PXa, a second liquid crystal capacitor Clcb and a secondstorage capacitor Cstb that are coupled to the switching element Q to beprovided in the second subpixel PXb, and an auxiliary capacitor Cas thatis provided between the switching element Q and the second liquidcrystal capacitor Clcb.

The switching element Q is a three-terminal element such as a TFT or thelike that is disposed in the lower display panel, a control terminalthereof is connected to the gate line GL, an input terminal thereof iscoupled to the data line DL, and an output terminal thereof is connectedto the first liquid crystal capacitor Clca, the first storage capacitorCsta, the auxiliary capacitor Cas.

One terminal of the auxiliary capacitor Cas is connected to the outputterminal of the switching element Q, and the other terminal thereof isconnected to the second liquid crystal capacitor Clcb and the secondstorage capacitor Cstb.

The charged voltage of the second liquid crystal capacitor Clcb is lowerthan the charged voltage of the first liquid crystal capacitor Clcathrough the action of the auxiliary capacitor Cas, thereby improving theside visibility of the LCD.

Hereinafter, an exemplary embodiment of FIG. 16 will be described.

An LCD according to the exemplary embodiment of the invention includessignal lines including a plurality of gate lines GLn and GL(n+1), aplurality of data lines DL, and a plurality of storage electrode linesSL, and a plurality of pixels PX connected thereto. Each pixel PXincludes a pair of first and second subpixels PXa and PXb, a firstsubpixel electrode is provided in the first subpixel PXa, and a secondsubpixel electrode is provided in the second subpixel PXb.

The LCD according to the exemplary embodiment of the invention furtherincludes a first switching element Qa and a second switching element Qbconnected to the gate line GLn and the data line DL, a first liquidcrystal capacitor Clca connected to the first switching element Qa to beprovided in a first subpixel PXa, a second liquid crystal capacitor Clcbconnected to the first storage capacitor Csta and the second switchingelement Qb to be provided in a second subpixel PXb, a third switchingelement Qc which is connected to the second switching element Qc and isswitched by the gate line GL(n+1) in the next stage, and an auxiliarycapacitor Cas which is connected to the third switching element Qc.

The first switching element Qa and the second switching element Qb arethree terminal elements, such as TFTs which are disposed in the lowerdisplay panel, control terminals are connected to the gate line GLn,input terminals are connected to the data line DL, and output terminalsare connected to the first liquid crystal capacitor Clca and the firststorage capacitor Csta, and the second liquid crystal capacitor Clcb andthe second storage capacitor Cstb, respectively.

The third switching element Qc is also a three terminal element such asa TFT which is provided in the lower display panel 100, a controlterminal is connected to the gate line GL(n+1) of the next stage, and aninput terminal is connected to the second liquid crystal capacitor Clcb,and an output terminal is connected to the auxiliary capacitor Cas.

One terminal of the auxiliary capacitor Cas is connected to the outputterminal of the third switching element Qc and the other terminal isconnected to the storage capacitor SL.

An operation of the LCD according to the exemplary embodiment of theinvention will be described. When a gate-on voltage is applied to thegate line GLn, the first switching element Qa and the second switchingelement Qb, which are connected thereto, are turned on, and the datavoltage of the data line 171 is applied to the first and second subpixelelectrodes.

Next, when a gate-off voltage is applied to the gate line GLn and agate-on voltage is applied to the gate line GL(n+1) of the next stage,the first and second switching elements Qa and Qb are turned off and thethird switching element Qc is turned on. As a result, charges of thesecond subpixel electrode which is connected to the output terminal ofthe second switching element Qb flows into the auxiliary capacitor Casso that the voltage of the second liquid crystal capacitor Clcb islowered.

As such, the side visibility of the LCD may be improved by differentlyadjusting the charged voltages of the first and second liquid crystalcapacitors Clca and Clcb.

Next, an exemplary embodiment of FIG. 17 will be described.

An LCD according to the exemplary embodiment of the invention includessignal lines including a plurality of gate lines GL, a plurality of datalines DL1 and DL2, and a plurality of storage electrode lines SL and aplurality of pixels PX connected thereto. Each pixel PX includes a pairof first and second liquid crystal capacitors Clca and Clcb and firstand second storage capacitors Csta and Cstb.

Each subpixel includes one liquid crystal capacitor and one storagecapacitor and further includes one TFT Q. The TFTs Q of two subpixels inone pixel are connected to the same gate line GL, but connected todifferent data lines DL1 and DL2. The different data lines DL1 and DL2simultaneously apply different levels of data voltages so that the firstand second liquid crystal capacitors Clca and Clcb of the two pixelshave different charging voltages. As a result, the side visibility ofthe LCD may be improved.

An exemplary embodiment of the invention corresponding to the exemplaryembodiment of FIG. 17 will be described in detail with reference toFIGS. 18 and 19 before a pixel structure is described with reference toFIG. 20.

FIG. 18 is a schematic diagram of a pixel according to the exemplaryembodiment of FIG. 17.

In the exemplary embodiment of FIG. 18, a gate conductor including agate line 121 and a storage electrode line 131 is disposed on a firstinsulation substrate including transparent glass or plastic. The gateline 121 includes gate electrodes 124 a and 124 b and a wide gate pad(not illustrated) for contact with another layer or an external drivingcircuit.

The gate line 121 is disposed to traverse a pixel area in an extendingdirection of rows. A pair of subpixel electrodes for displayingdifferent grays is disposed at opposite ends of the gate line 121. Inthe exemplary embodiment of FIG. 18, the first subpixel electrode 191 afor displaying a high gray is disposed above the gate line 121, and thesecond subpixel electrode 191 b for displaying a low gray is disposedbelow the gate line 121.

The storage electrode line 131 may include the same material as that ofthe gate line 121, and may be provided by using the same process as thatof the gate line 121.

The first storage electrode line 131 disposed above the gate line 121may have such a quadrangular shape so as to surround the first subpixelelectrode 191 a. An upper side and a lower side of the quadrangularshaped first storage electrode line 131 may be out of one pixel area soas to horizontally extend to be connected to another layer or anexternal driving circuit. Further, the lower side of the first storageelectrode line 131 has an extending structure that is downwardlyextended to a first contact hole 185 a. This extending structure may notbe included according to another exemplary embodiment.

On the gate conductor, the gate conductor is covered by a gateinsulating layer 140 (refer to FIG. 2). A conduct hole is defined at aportion of the gate conductor which corresponds to the gate pad (notillustrated) to expose the gate pad. The portions of the gate conductorother than the conduct hole may be covered by the gate insulating layer140.

Semiconductor layers including a first semiconductor layer 154 a and asecond semiconductor layer 154 b are disposed on the gate insulatinglayer 140. The semiconductor layers other than the first semiconductorlayer 154 a and the second semiconductor layer 154 b are disposed belowthe region at which a data conductor including first and second datalines 171 a and 171 b, first and second source electrodes 173 a and 173b, and first and second drain electrodes 175 a and 175 b is disposed.This structure is provided in the case that a semiconductor layer isetched together with a data conductor when the data conductor is etched,the first semiconductor layer 154 a and the second semiconductor layer154 b forming a channel of the TFT are disposed to correspond to aphotoresist corresponding to a transflective region or a slit region ona mask.

The semiconductor layer may include an amorphous silicon semiconductor,an oxide semiconductor, or a polycrystalline semiconductor.

A plurality of ohmic contacts (not illustrated) may be disposed on thesemiconductors other than the first semiconductor layer 154 a and thesecond semiconductor layer 154 b, and may be omitted when thesemiconductor layer includes an oxide semiconductor.

A data conductor is disposed on the ohmic contacts.

The data conductor includes first and second data lines 171 a and 171 b,a first source electrode 173 a, a second source electrode 173 b, a firstdrain electrode 175 a, and a second drain electrode 175 b.

The first and second data lines 171 a and 171 b are extended along leftand right edges of one pixel area in an extending direction, and eachincludes the first source electrode 173 a and the second sourceelectrode 173 b. The first source electrode 173 a and the second sourceelectrode 173 b may have a U-shape, but are not limited thereto.

The data line 171 includes a wide data pad (not illustrated) forconnection with another layer or an external driving circuit.

The first drain electrode 175 a is disposed to face the first sourceelectrode 173 a and has, for example, an I-shape corresponding to theU-shaped first source electrode 173 a, and includes a widely expandedregion that is connected to the first subpixel electrode 191 a.

Similarly, the second drain electrode 175 b is disposed to face thesecond source electrode 173 b and has, for example, an I-shapecorresponding to the U-shaped second source electrode 173 b, andincludes a widely expanded region that is connected to the secondsubpixel electrode 191 b.

The data conductor, the ohmic contacts, and the semiconductor layer maybe simultaneously provided by using one mask.

The first gate electrode 124 a, the first source electrode 173 a, andthe first drain electrode 175 a constitute one first TFT Qa togetherwith the first semiconductor layer 154 a, and a channel of the first TFTis defined at the first semiconductor layer 154 a disposed between thefirst source electrode 173 a and the first drain electrode 175 a.Similarly, the second gate electrode 124 b, the second source electrode173 b, and the second drain electrode 175 b constitute one second TFT Qbtogether with the second semiconductor layer 154 b, and a channel isdefined at the second semiconductor layer 154 b between the secondsource electrode 173 b and the second drain electrode 175 b.

A first passivation layer is disposed on the data conductor and theexposed semiconductor layers 154 a and 154 b. In an exemplaryembodiment, the first passivation layer may include a silicon nitride, asilicon oxide, or the like that is used to form an inorganic insulatinglayer, for example. The second passivation layer is disposed on thefirst passivation layer 180 p, and may include an organic material,unlike the first passivation layer. According to another exemplaryembodiment, one of the first passivation layer and the secondpassivation layer may be omitted. According to another exemplaryembodiment, a color filter may be disposed at the position of the secondpassivation layer. In this case, the first passivation layer 180 p mayserve to prevent a pigment of the color filter from flowing into theexposed semiconductor layers 154 a and 154 b. Even when the color filteris disposed, the second passivation layer may be provided to cover thecolor filter.

A first contact hole 185 a and a second contact hole 185 b are definedin the first and second passivation layers to expose the first andsecond drain electrodes 175 a and 175 b, respectively.

First and second subpixel electrode 191 a and 191 b may be disposed onthe second passivation layer.

The first and second subpixel electrode 191 a and 191 b may beseparately disposed with the gate line 121 therebetween to be adjacentto each other in the column direction. The first subpixel electrode 191a is disposed in the high gray subpixel area, and the second subpixelelectrode 191 b is disposed in the low gray subpixel area.

The first subpixel electrode 191 a and the second subpixel electrode 191b respectively include one horizontal stem 193 a and 193 b, and onevertical stem 194 a and 194 b, and further include a plurality of minutebranches 197 a and 197 b which is obliquely extended therefrom.

In this case, the minute branches 197 a are arranged in two directions,and thus the first subpixel electrode 191 a or the second subpixelelectrode 191 b has two domains. The structure of the first subpixelelectrode 191 a or the second subpixel electrode 191 b including twodomains is referred to as one unit pixel electrode.

As illustrated in FIG. 18, the low gray subpixel area is about 1.5 timesto about 2.5 times larger than the high gray subpixel area. As such,although the two subpixel areas are different from each other, onehorizontal stem and one vertical stem are provided in each of the twosubpixel areas according to the exemplary embodiment of the invention.In other words, according to an exemplary embodiment of the invention,the first and second subpixel electrodes 191 a and 191 b respectivelyinclude the minute branches 197 a and 197 b, each of which is arrangedin two directions, and thus each includes two domains. These two domainsare fewer than the four the domains of one general subpixel electrode.

Although the pixel size gets smaller in a higher resolution LCD, apredetermined number of minute branches or stems may be provided to havea predetermined size. In the exemplary embodiment of the invention, onestem is provided in one subpixel area, and thus the texture generated inthe pixel area can be controlled, display errors can be reduced, andlight transmittance can be improved.

Further, in the case of providing a curved display device, it ispossible to reduce display errors caused by misalignment between upperand lower substrates through the pixel electrode that is extended fromthe horizontal stem. As a result, the LCD according to the exemplaryembodiment of the invention can be applied to a curved LCD having acurved structure as well as a general LCD having a flat structure. Inparticular, the LCD according to the exemplary embodiment of theinvention has relatively further improved characteristics in the curvedstructure compared to other pixel structures.

In an exemplary embodiment, the first and second subpixel electrodes 191a and 191 b may include a transparent material such as ITO and IZO.

An upper display panel will now be described. Although not illustrated,the upper display panel is a constituent element that is required toaccommodate a liquid crystal layer in the LCD. However, in an LCDincluding an additional structure for accommodating the liquid crystallayer, the upper display panel may be omitted.

The upper display panel included in an LCD will be described.

A light blocking member (not illustrated) is disposed on a secondinsulation substrate (not illustrated) disposed to face a firstinsulation substrate 110 including transparent glass, plastic, or thelike. The light blocking member is also referred to as a black matrixand prevents light leakage. The light blocking member which is describedto be disposed in the upper display panel may be disposed in a lowerdisplay panel according to another exemplary embodiment.

In the exemplary embodiment, the light blocking member may be disposedto extend along the data line 121 and the first and second data lines171 a and 171 b in an extending direction of columns.

A plurality of color filters (not illustrated) is also disposed on thesecond insulation substrate.

An overcoat (not illustrated) may be disposed on the color filters andthe light blocking member. In an exemplary embodiment, the overcoat mayinclude an organic insulator, to serve to remove steps caused by thecolor filters and the light blocking member and provide a flat surface.In another exemplary embodiment, the overcoat may be omitted.

A common electrode 270 (refer to FIG. 8) is disposed on the overcoat.The common electrode 270 may include the same material as that of thepixel electrode 191 (refer to FIG. 8), and may be provided in a flatsurface type to receive a common voltage.

Further, an alignment layer (not illustrated) may be disposed inside thepixel electrode 191 and the common electrode 270.

A liquid crystal layer (not illustrated) may be disposed inside thealignment layer between the lower display panel and the upper displaypanel. In an exemplary embodiment, the liquid crystal layer has negativedielectric anisotropy, and liquid crystal molecules of the liquidcrystal layer are aligned such that long axes thereof are perpendicularto surfaces of the upper and lower display panels in a state in which noelectric field is generated.

The first and second subpixel electrodes 191 a and 191 b to which thedata voltage is applied generate an electric field along with the commonelectrode 270 of the upper display panel 200, thereby determining thealignment directions of the liquid crystal molecules of the liquidcrystal layer interposed between the two electrodes 191 and 270.Depending on the determined directions of the liquid crystal molecules,a phase difference of light passing through the liquid crystal layer isvaried, and thus an amount of light passing through the polarizer isadjusted to control display luminance.

In the above exemplary embodiments, the pixel structure of the LCD inwhich one horizontal stem 193 b and one vertical stem 194 b are providedeven in the low gray subpixel area was described.

Hereinafter, adjacent pixels will be described with reference to FIG.19.

FIG. 19 is a plan view of a pixel according to the exemplary embodimentof FIG. 18.

Additional arrows illustrated in FIG. 19 indicate alignment directionsof the liquid crystal molecules, and the adjacent pixels have a facingstructure to face each other.

Although the facing structure is illustrated in FIG. 19, the adjacentpixels may have a same-directional structure.

Hereinafter, an equivalent circuit of a pixel in which differentvoltages are applied to two subpixel electrodes according to anexemplary embodiment will be described with reference to FIG. 20.

The LCD according to an exemplary embodiment of the invention, as shownin FIG. 20, includes a gate line GL, a data line DL, a first power lineSL1, a second power line SL2, and a first switching element Qa and asecond switching element Qb, which are connected to the gate line GL andthe data line DL.

The LCD according to an exemplary embodiment of the invention furtherincludes an auxiliary step-up capacitor Csa which is connected to thefirst switching element Qa, a first liquid crystal capacitor Clca, anauxiliary step-down capacitor Csb which is connected to the secondswitching element Qb, and a second liquid crystal capacitor Clcb.

The first switching element Qa and the second switching element Qbinclude three terminal elements such as TFTs. The first switchingelement Qa and the second switching element Qb are connected to the samegate line GL and the same data line DL to be turned on at the same time,thereby outputting the same data signal.

A voltage which swings with a predetermined period is applied to thefirst power line SL1 and the second power line SL2. A first low voltageis applied to the first power line SL1 during a predetermined period(e.g., one horizontal period 1H) and a first high voltage is appliedthereto during a next predetermined period. A second high voltage isapplied to the second power line SL2 during a predetermined period and asecond low voltage is applied thereto during a next predeterminedperiod. In this case, the first period and the second period arerepeated multiple times for one frame so that a swinging voltage isapplied to the first power line SL1 and the second power line SL2. Inthis case, the first low voltage is equal to the second low voltage andthe first high voltage is equal to the second high voltage.

The auxiliary step-up capacitor Csa is connected to the first switchingelement Qa and the first power line SL1, and the auxiliary step-downcapacitor Csb is connected to the second switching element Qb and thesecond power line SL2.

A voltage Va of a terminal (hereinafter, referred to as a “firstterminal”) at a portion at which the auxiliary step-up capacitor Csa isconnected to the first switching element Qa is lowered when the firstlow voltage is applied to the first power line SL1 and rises when thefirst high voltage is applied. Thereafter, the voltage Va of the firstterminal swings as a voltage of the first power line SL1 swings.

Similarly, a voltage Vb of a terminal (hereinafter, referred to as a“second terminal”) at a portion at which the auxiliary step-up capacitorCsb is connected to the second switching element Qb is lowered when thesecond high voltage is applied to the second power line SL2 and riseswhen the second high voltage is applied. Thereafter, the voltage Vb ofthe second terminal swings as a voltage of the second power line SL2swings.

As such, although the same data voltage is applied to two sub-pixels,the voltages Va and Vb of the pixel electrodes of two sub-pixels arevaried according to the magnitude of the voltages swung in the first andsecond power lines SL1 and SL2, and thus the transmittance of the twosub-pixels is controlled differently, thereby improving the sidevisibility.

In the above, various exemplary embodiments of the invention weredescribed.

In the above LCDs, the unit pixel electrode pertaining to the pixelelectrode has the minute branches 197, and since the number of unitpixel electrodes is high, the number of the minute branches 197 is high.As a result the liquid crystal control force to control the liquidcrystal molecule may be sufficiently obtained, and thus a prepolymerpolymerized by light may not be additionally included in the liquidcrystal layer.

However, according to another exemplary embodiment, the liquid crystalcontrol force may be partially decreased, and thus the prepolymer may beincluded in the liquid crystal layer.

A method of forming the pretilt in the case of including the prepolymerwill be described with reference to FIG. 21.

FIG. 21 illustrates a process for providing a pretilt to liquid crystalmolecules by using prepolymers that are polymerized by light such asultraviolet rays.

Referring to FIG. 21, prepolymers 330 such as a monomer that ispolymerized by light such as ultraviolet rays are first injected alongwith a liquid crystal material between the two display panels 100 and200. The prepolymer 330 may be a reactive mesogen that is polymerized bylight such as ultraviolet rays.

Next, an electric field is generated at the liquid crystal layer 3between two display panels 100 and 200 by respectively applying a datavoltage and a common voltage to the first and second subpixel electrodesand the common electrode 270 of the upper display panel 200. Thus,liquid crystal molecules 31 of the liquid crystal layer 3 are inclinedin a predetermined direction in response to the electric field.

As such, when light from ultraviolet rays is irradiated in the statethat the liquid crystal molecules 31 of the liquid crystal layer 3 areinclined in the predetermined direction, the prepolymer 330 ispolymerized, and thus a pretilt providing polymer 350 is provided asshown in FIG. 21. The pretilt providing polymer 350 contacts the displaypanels 100 and 200. Alignment directions of the liquid crystal molecules31 are determined such that the liquid crystal molecules 31 have pretiltas in the aforementioned directions. Accordingly, the liquid crystalmolecules 31 are arranged to have pretilt corresponding to fourdifferent directions even in a state in which a voltage is not appliedto the field generating electrodes 191 and 270 (refer to FIG. 8).

As a result, the liquid crystal molecules 31 have the pretilt of fourdirections in each region of the upper and lower subpixels of one pixel.

The pretilt using the polymer as shown in FIG. 21 is additionally usedin the case that the texture is not reduced through the control for theliquid crystal control force provided by the minute branches 197 (referto FIG. 8).

The exemplary embodiment of FIG. 21 has been described based on the casethat the liquid crystal layer includes a photo-reactive material, butthis is true of the case that the alignment layer may include thephoto-reactive material.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A liquid crystal display comprising: a firstinsulation substrate; a gate line; a data line configured to cross thegate line and be insulated therefrom; a thin film transistor connectedto the gate line and the data line; a pixel electrode configured toinclude: a first subpixel electrode connected to the thin filmtransistor; and a second subpixel electrode; a second insulationsubstrate configured to face the first insulation substrate; a commonelectrode disposed on the second insulation substrate; and a liquidcrystal layer disposed between the first insulation substrate and thesecond insulation substrate and includes a plurality of liquid crystalmolecules, wherein each of the first subpixel electrode and the secondsubpixel electrode includes a unit pixel electrode including a pluralityof minute branches which is extended from a horizontal stem and avertical stem.
 2. The liquid crystal display of claim 1, wherein theunit pixel electrode has two domains having different alignmentdirections of the plurality of liquid crystal molecules from each other.3. The liquid crystal display of claim 2, wherein a region at which thefirst subpixel electrode is disposed is a first subpixel area and aregion at which the second subpixel electrode is disposed is a secondsubpixel area, the vertical stem is adjacent to a vertical side of thefirst subpixel area and the second subpixel area, an end of thehorizontal stem is connected to a center of the vertical stem, and theplurality of minute branches obliquely extends from the vertical stemand the horizontal stem toward the horizontal stem.
 4. The liquidcrystal display of claim 3, wherein the first subpixel electrode has astructure in which the vertical stem is disposed at a right side and thehorizontal stem is extended from the right side to a left side, and theplurality of minute branches is extended in at least one of an upperright direction and a lower right direction, and the second subpixelelectrode has a structure in which the vertical stem is disposed at theleft side and the horizontal stem is extended from the left side to theright side, and the plurality of minute branch is extended in at leastone of an upper left direction and a lower left direction.
 5. The liquidcrystal display of claim 4, wherein a width of each of the firstsubpixel electrode and the second subpixel electrode is equal to or lessthan about 140 micrometers.
 6. The liquid crystal display of claim 5,wherein a width of at least one of the vertical stem and the horizontalstem is equal to or less than about 25 micrometers.
 7. The liquidcrystal display of claim 4, further comprising: a third subpixelelectrode configured to be adjacent to one of a left side and a rightside of the first subpixel electrode; and a fourth subpixel electrodeconfigured to be adjacent to one of a left side and a right side of thesecond subpixel electrode, wherein the third subpixel electrode and thefirst subpixel electrode have a facing structure, and the fourthsubpixel electrode and the second subpixel electrode have a facingstructure.
 8. The liquid crystal display of claim 7, further comprisinga shielding electrode disposed between adjacent subpixel electrodes,above the data line, and the shielding electrode and the subpixelelectrode are disposed on a same layer.
 9. The liquid crystal display ofclaim 7, further comprising a shielding electrode disposed betweenadjacent subpixel electrodes, above the data line, wherein the shieldingelectrode is disposed at a layer which is lower than that of thesubpixel electrode to partially overlap the subpixel electrode.
 10. Theliquid crystal display of claim 9, wherein alignment directions of theplurality of liquid crystal molecules which are aligned by the firstsubpixel electrode and the third subpixel electrode adjacent thereto arethe same, and alignment directions of the plurality of liquid crystalmolecules which are aligned by the second subpixel electrode and thefourth subpixel electrode adjacent thereto are the same.
 11. The liquidcrystal display of claim 4, further comprising: a third subpixelelectrode configured to be adjacent to one of a left side and a rightside of the first subpixel electrode; and a fourth subpixel electrodeconfigured to be adjacent to one of a left side and a right side of thesecond subpixel electrode, wherein the third subpixel electrode and thefirst subpixel electrode have a same directional structure, and thefourth subpixel electrode and the second subpixel electrode have a samedirectional structure.
 12. The liquid crystal display of claim 4,further comprising: a divided reference voltage line extended in anextending direction of the data line, to include a horizontal portionand a vertical portion.
 13. The liquid crystal display of claim 12,wherein the vertical portion of the divided reference voltage lineoverlaps the first subpixel electrode and the vertical stem of thesecond subpixel electrode.
 14. The liquid crystal display of claim 13,wherein the horizontal portion of the divided reference voltage line isoverlapped with horizontal sides of the first subpixel area and thesecond subpixel area, and thus is overlapped with a horizontal end ofthe plurality of minute branches of the first subpixel electrode and thesecond subpixel electrode.
 15. The liquid crystal display of claim 12,wherein the thin film transistor disposed between a thin film transistorforming region provided between the first subpixel area and the secondsubpixel area includes: a first thin film transistor connected to thegate line, the data line, and the first subpixel electrode; a secondthin film transistor connected to the gate line, the data line, and thesecond subpixel electrode; and a third thin film transistor connected tothe gate line, the divided reference voltage line, and the secondsubpixel electrode.
 16. The liquid crystal display of claim 4, whereinthe thin film transistor disposed between a thin film transistor formingregion provided between the first subpixel area and the second subpixelarea includes: a first thin film transistor connected to the gate line,the data line, and the first subpixel electrode; and a second thin filmtransistor connected to the gate line, the data line, and the secondsubpixel electrode.
 17. The liquid crystal display of claim 4, furthercomprising: a color filter disposed on at least one of the firstinsulation substrate and the second insulation substrate; and a lightblocking member disposed on at least one of the first insulationsubstrate and the second insulation substrate.
 18. The liquid crystaldisplay of claim 17, wherein the light blocking member is provided in anextending direction of the gate line.
 19. The liquid crystal display ofclaim 4, wherein the liquid crystal display is a curved liquid crystaldisplay.